Ice machine compressor



May 23, 1933. ow 1,910,636

ICE MACHINE COMPRES SOR Filed Nov. 19, 1929 2 Sheets-Sheet l ay 1933- G. L. POWNALL ICE MACHINE COMPRESSOR Filed Nov. 19, 1929 2 Sheets-Sheet 2 Patented May 23, 1933 GEORGE L. POWNALL, OF ATLANTA, GEORGIA 7 ICE MAOHINE COMPRESSOR Application filed November 19, 1929. Serial No. 408,366.

My invention relates to improvements in ice machine compressors. One of its objects is to provide an improved ice machine compressor in which a straight driving shaft is employed in place of a crank shaft and the pistons are actuated in the cylinders by means of rollers traveling in eccentric or cam grooves in a head carried by the driving shaft. Another object is to avoid passage of theammonia or other refrigerating gas through the crank case. Another object is to provide for driving a plurality of pistons from a single eccentric or cam groove. nother object is to provide an improved drivr ing head structure and means for connecting therewith and actuating the pistons therefrom. Anotherobject is to secure a direct driving thrust or reciprocatory movement of the pistons relative to a straight driving shaft. My invention also comprises certain details of form and arrangement and combination of components, all of which will be fully set forth in the description of the accompanying drawings, in which:

Fig. 1 is a diagrammatic view of an ice machine showing my improved compressor in end elevation and attached to the cooling and condensing elements.

Fig. 2 is a perspective view of the central section of the driving head, detached.

Fig. 3 is a perspective view of one of the end sections of the driving head detached.

Fig. 4; is a vertical section through the compressor taken on line 44 of Fig. 1.

Fig. 5 is a vertical section through the compressor taken on line 5 -5 of Fig. 4.

Fig. 6 is a detail of the inner end of one of the pistons detached. 7

Fig. 7 illustrates a modification of Fig. 6.

The accompanying drawings illustrate embodiments of my invention in which 15 represents the condenser of an ice or refrigerating machine and 16 the cooling member of an ice or V refrigerating apparatus immersed in a container of brine 17. An expansion valve18 is adjustable to permit a regulated quantity of liquefied refrigerant to escape through said valve from the lower oortion of the condenser 15 into the cooling member 16, where the refrigerant expands and has a cooling effect. The vaporous refrigerant is taken from the cooling member 16 into the cylinders 20 of the compressor 21, preferably through the side walls of the cylinders, and after being compressed in the cylinders is ejected from the cylinders into the upper portion of the condenser in a heated condition, where heat is extracted, as for instance by dripping cooling Water over the exterior of the condenser. As soon as the heat has been extracted from the compressed refrigerant in the condenser the refrigerant liquefies and accumulates as a liquid in the lower portion of the condenser ready to be drawn again from the condenser into the cooling member.

It has been customary heretofore to drive the'pistons of the compressor by means of a crank shaft having one or more cranks thereon, depending upon the number of cylinders in the compressor and operatively connecting the pistons of the respective cylinders to' the cranks of the crank shaft by means of connecting rods or pitmen. This practice is objectionable in several'respects. It requires, to be eflicient, the use of connecting rods of lengths three or more times the stroke of the pistons, and hence prevents concentration of the compressor within reasonable dimensions, particularly where small cooling units are required. The crank shafts are also elements of weakness and are liable to spring or yield under strain, require ex cessive housing space, and are of relatively short life under heavy duty. They are also expensive to produce and repair and maintain in operative condition. It is also difficult to keep the refrigerant from entering the crank case and mixing with the lubricant.

In my improved compressor I employ a straight or through shaft 24 supported in a blind or closed bearing 25 at one end of the compressor, and in a bearing 26 through which the shaft 24 extends to the exterior of the compressor at the opposite end of the compressor. Mounted rigidly upon the shaft 24 for instance by means of a key 27, or a drive fit is a driving member 30 having two plane faces 28, and two eccentric boxes or hubs 29. The eccentric hubs 29 are pistons.

set one hundred and eighty degrees apart on the shaft 24. Outside of the hubs 29 are mounted rigidly upon the shaft 24 end driving head sections 32 each having an inwardly turned rim or ledge 34 which is eccentric to the shaft 24 and concentric with the periphery of the hub against which it abuts. The shaft 24 and the driving members mounted thereon are encased in a housing 21 having heads 36 and 37 detachably attached to opposite ends thereof and a man-hole plate 38 detachably attached to one side thereof.

I have illustrated two cylinders 40 detachably attached above the housing 35 and pistons 42 mounted to reciprocate vertically within said cylinders. Other cylinders may be attached to the sides of the housing if desired, to provide for driving two or more pistons from each eccentric or cam groove of the driving head. Each cylinder is provided with a gas inlet port 43 and a gas exit port 44. An exit valve 45 of any approved type is mounted in the cylinder above the piston. An inlet valve 46 of any approved type is mounted upon the outer end of the piston. The pistons are hollow and closed at each end, except for the exit ports 47 covered by the inlet valves 46. Each piston has a port 49 in its side wall opposite the inlet port through the side of the cylinder wall and the ports 49 are of suflicient length to register with the cylinder inlet ports 43 through substantially the entire stroke of the The pistons are provided with packing rings 50 both above and below the ports 49.

At the inner ends of the pistons are inwardly extending pivoted projections 52',

1 which enter the annular recesses 53 between the driving members 30 and 32. At their inner ends the projections 52 are provided with one or more stud shafts 54, upon which are mounted rollers 55. The peripheries of the rollers bear against the periphery of the hub 29 at one side and at their opposite sides bear against the inner face of the ledgers 34. As illustrated in Fig. 6 each projection 52 is provided with two stud shafts 54 and two rollers 55, but a single stud shaft 54 and roller 55 in alignment with the piston axis as shown in Fig. 7, may be employed for each projection 52 if desired. The engagement of the pistons with the cylinders is of sufficient length to guide the pistons and their projections 52 axially of the cylinders. The thrust from the driving members upon the pistons is positive'in both directions and axially of the pistons and cylinders, and exerts practically no lateral thrust upon the cylinder walls. Packing rings tend to prevent leakage through from the interior of the housing to the bearings, while a splash system serves to feed lubricant to the lubricant ducts 62 and lubricate the bearings and seal them against leakage. The splash system also lubricates the shaft 24, the driving members 30 and 34, the projections 52, stud shafts 54, and rollers 55, including all contacting surfaces within the compressor housing and cylinders requiring lubrication. If desired the driving members may be held in place relative to the member 30 by means of countersunk screws 64, tapped into the hubs 29. The bearing 26 is furtherprotected against leakage by means of a series of packing rings 66, interposed springs 67, and a threaded cap 68.

Where two rollers 55 are employed as shown in-Fig. 6, said-rollers are mounted upon studs 54 carried by a cross-bar 72 which is pivotally attached at 74 to the member 52, and which cross-bar has a limited rocking movement relative to the member 52, to permit the rollers 55 to track readily in the cam groove, and relieve the rollers 55 and members 52 from lateral strain.

WVhile the mechanism as a whole is more compact and occupies less space than a crank shaft driven compressor, the pistons are longer than pistons of usual construction and serve as large surface guides to guide and support the rollers 55 and members 52 and to take the lateral strain. The spaces within the pistons serve as reservoirs for the storage of a sufficient body of gas close to the gas inlet valves, and thus insure the cylinders receiving a full charge of gas at each stroke. If desired lubricant may be positively forced by means of a lubricant pump to the bearings and parts requiring lubrication, inde pendently of the splash system.

In the event of the periphery of. the rollers 55 becoming worn, the rollers can be readily replaced at small expense. I contemplate employing ball or roller antifric'tion' bearings between the rollers 55 and their stud shafts 54, which bearings are preferably capable of adjustment to compensate for wear.

If desired the cylinders and cylinder heads may be provided with threaded bosses 7 7 and 7 8 upon opposite sides, to enable the gas intake and gas exit conduits 43 and 44 to be connected either right hand or left hand to the compressors, as maybe most convenient.

The heads 36 and 37 are preferably made of sufficient diameter so that upon detaching the heads 36 and 37, the driving shaft and members thereon may be removed from the casing, or any portion thereof removed or' reached for adjustment or renewal, particularly the heads 32 and rollers 55.

The apparatus herein shown and described is capable of considerable modification within the scope of the claims without departing from the spirit of my invention.

What I claim is:

1. The combination with a pair of parallel reciprocable members, of a straight driving shaft, a disc mounted concentrically of said shaft, said disc having a pair of eccentric extensions disposed one each on opposite sides of the disc, degrees apart and having said shaft extending through them, a pair of cam plates rigidly mounted on the shaft and each having an interior annular flange concentric with one of said eccentric extensions on the disc, a roller member on the end of each of the said reciprocable members and engaging said eccentric members and annular flanges respectively at all times When the driving shaft is rotated thereby producing constant rectilinear movement of the reciprocable members.

2. Mechanism of the class described comprising in combination a straight driving shaft, a disc mounted concentrically of said shaft, and an eccentric extension on one face of the disc and having the shaft extending therethrough, a cam plate rigidly mounted on the shaft and having an interior annular flange concentric With said eccentric extension on the disc, a reciprocable member extending between the disc and cam plate and a roller member on the end of the reciprocable member and engaging the eccentric member and the annular flange respectively at all times When the driving shaft is rotated thereby producing constant rectilinear movement of the reciprocable member.

In testimony whereof I have aflixed my signature.

GEORGE L. POWNALL. 

